James b



the difference of speed of the two rolls-that is to say, if the slower roll A has thirty lines per inch of periphery, and the fast roll A is running at a differential speed of two and onehalf times greater than the slow roll A, then the fast roll A would have twelve lines per inch, (12 2l=30;) but as more or less of the Cutting or granulating` quality may be desired for different classes of work, or to suit the pleasure of the miller, the relative number oi' lines on the fast roll A may be more orless and the quality of work correspondingly varied. It will be observed that when a roll is scratched with lines, as described, the face of the roll between the lines remains smooth and performs to some extent the crushingeifeet, while the lines produce the granulating` elleet; and, also, that by having in the fast roll A more land and less lines than in the slow roll A,the action of the two rolls is more nearly equalized, as these differences are more nearly proportioned to their speed; and, further, that just as the granulating action is made to preponderate by having` more lines, or subdued by having,` less lines,on the fast roll A, so the combined qualities are made more or less severe, and the result regulated as desired.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

l. In a roller grinding-mill, a pair of co-operating` rolls, both having smooth surfaces, provided with lines or scratches and adapted to be driven at different rates of peripheral speed, the fast-speeded roll having` a less number ot' lines per inch of periphery than thel slow-speeded roll.

2. In a rollergrinding-mill, the combination 

